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Forestry activity is one mechanism of invasion by arboreal plants

Journal of Arid Land 2013年第4期5卷 434-438页

作者： Gulnara SITPAEVA sergey chekalin The Institute of Botany and Phytointroduction Committee of ScienceMinistry of Education and ScienceAlmaty 050060Kazakhstan

For a long time,forestry primarily had industrial *** of wood production was the main criterion of forestry efficacy,and thus rapid-growing arboreal species were cultivated in natural *** recently,nature protection has become one of forestry＇s ***,some introduced,rapid-growing species became aggressive components of natural ecological systems during the *** this paper,we first describe a method that we developed to categorize aggressiveness of invasive arboreal plants in natural forest ecosystems of *** then apply this new scheme to monitoring data of invasive arboreal plants to provide an insight into the invasion potential of different species in the fruit forests of Southeast Kazakhstan.

关键词： forest ecosystems aggressiveness invasive arboreal plants

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Phase-matched third-harmonic generation via doubly resonant optical surface modes in 1D photonic crystals

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Light(Science & Applications) 2016年第1期5卷 424-429页

作者： Valery N Konopsky Elena V Alieva sergey Yu Alyatkin Alexey A Melnikov sergey V chekalin Vladimir M Agranovich Institute of Spectroscopy Fizicheskaya5TroitskMoscow 142190Russia Moscow Institute of Physics and Technology Institutskiy per.9Dolgoprudny 141700Russia

Efficient nonlinear conversion requires that interacting optical waves maintain a consistent phase relationship when traveling in a medium despite its *** phase-matching,which is often used to compensate for the dispersion,is not applicable to optically isotropic nonlinear ***,we present a one-dimensional photonic crystal structure that allows the propagation of optical surface waves,both at the fundamental and third-harmonic frequencies,as an efficient medium for phasematched third-harmonic generation.A unique advantage of this structure is that the effective refractive indices for the surface waves are similar to the refractive index of air at both *** allows phase-matching between the first and third harmonics,and a visible collinear beam of the third harmonic is produced at the prism-coupled ***,these optical surface waves propagate over long distances even if a lossy nonlinear nanofilm is deposited onto the photonic crystal *** provide experimental results for third-harmonic generation at a wavelength of 410 nm for a bare dielectric Ta2O5/SiO2 multilayer structure and for the same structure coated with a 15-nm GaAs film.

关键词： nonlinear optics optical surface waves photonic crystals

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Observation of nonlinear disclination states

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Light(Science & Applications) 2023年第9期12卷 1818-1829页

作者： Boquan Ren Antonina A.Arkhipova Yiqi Zhang Yaroslav V.Kartashov Hongguang Wang Sergei A.Zhuravitskii Nikolay N.Skryabin Ivan V.Dyakonov Alexander A.Kalinkin Sergei P.Kulik Victor O.Kompanets sergey V.chekalin Victor N.Zadkov Key Laboratory for Physical Electronics and Devices Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Institute of Spectroscopy Russian Academy of SciencesTroitskMoscow 108840Russia Faculty of Physics Higher School of EconomicsMoscow 105066Russia Quantum Technology Centre Faculty of PhysicsM.V.Lomonosov Moscow State UniversityMoscow 119991Russia

Introduction of controllable deformations into periodic materials that lead to disclinations in their structure opens novel routes for construction of higher-order topological insulators hosting topological states at *** of these topological states is consistent with the bulk-disclination correspondence principle,and is due to the filling anomaly that results in fractional charges to the boundary unit *** far,topological disclination states were observed only in the linear regime,while the interplay between nonlinearity and topology in the systems with disclinations has been never studied *** report here on the experimental observation of the nonlinear photonic disclination states in waveguide arrays with pentagonal or heptagonal disclination cores inscribed in transparent optical medium using the fs-laser writing *** transition between nontopological and topological phases in such structures is controlled by the Kekulédistortion coefficient r with topological phase hosting simultaneously disclination states at the inner disclination core and spatially separated from them corner-I,corner-II,and extended edge states at the outer edge of the *** show that the robust nonlinear disclination states bifurcate from their linear counterparts and that location of their propagation constants in the gap and,hence,their spatial localization can be controlled by their *** disclination states can be efficiently excited by Gaussian input beams,but only if they are focused into the waveguides belonging to the disclination core,where such topological states *** results open new prospects for investigation of nonlinear effects in topological systems with disclinations and are relevant for different areas of science,including Bose-Einstein and polariton condensates,where potentials with the disclinations can be created.

关键词： structure topological nonlinear

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Observation of nonlinear fractal higher order topological insulator

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Light(Science & Applications) 2024年第11期13卷 2699-2714页

作者： Hua Zhong Victor O.Kompanets Yiqi Zhang Yaroslav V.Kartashov Meng Cao Yongdong Li Sergei A.Zhuravitskii Nikolay N.Skryabin Ivan V.Dyakonov Alexander A.Kalinkin Sergei P.Kulik sergey V.chekalin Victor N.Zadkov Key Laboratory for Physical Electronics and Devices Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong University710049 Xi’anChina Institute of Spectroscopy Russian Academy of SciencesTroitskMoscow 108840Russia Quantum Technology Centre Faculty of PhysicsM.V.Lomonosov Moscow State UniversityMoscow 119991Russia Faculty of Physics Higher School of EconomicsMoscow 105066Russia

Higher-order topological insulators(HOTIs)are unique materials hosting topologically protected states,whose dimensionality is at least by 2 lower than that of the *** states in such insulators may be strongly confined in their corners which leads to considerable enhancement of nonlinear processes involving such ***,all nonlinear HOTIs demonstrated so far were built on periodic bulk lattice ***,we demonstrate the first nonlinear photonic HOTI with the fractal *** their fractional effective dimensionality,the HOTIs constructed here on two different types of the Sierpiński gasket waveguide arrays,may support topological corner states for unexpectedly wide range of coupling strengths,even in parameter regions where conventional HOTIs become *** demonstrate thresholdless spatial solitons bifurcating from corner states in nonlinear fractal HOTIs and show that their localization can be efficiently controlled by the input beam *** observe sharp differences in nonlinear light localization on outer and multiple inner corners and edges representative for these fractal *** findings not only represent a new paradigm for nonlinear topological insulators,but also open new avenues for potential applications of fractal materials to control the light flow.

关键词： materials. flow. topological

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振荡波导阵列中孤子的实验发现

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Science Bulletin 2023年第18期68卷 2017-2024,M0003页

作者： Antonina A.Arkhipova Yiqi Zhang Yaroslav V.Kartashov Sergei A.Zhuravitskii Nikolay N.Skryabin Ivan V.Dyakonov Alexander A.Kalinkin Sergei P.Kulik Victor O.Kompanets sergey V.chekalin Victor N.Zadkov Institute of Spectroscopy Russian Academy of SciencesTroitsk 108840Russia Faculty of Physics Higher School of EconomicsMoscow 105066Russia Key Laboratory for Physical Electronics and Devices(Ministry of Education) School of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Quantum Technology Centre Faculty of PhysicsM.V.Lomonosov Moscow State UniversityMoscow 119991Russia

时间参数周期变化的弗洛凯系统有助于发现常参数静态系统中不存在并常常伴有新颖拓扑态出现的非传统拓扑相.耦合系数被周期调制的Su-Schrieffer-Heeger晶格正是这种弗洛凯系统之一.尽管这个晶格在一半演化周期内处在拓扑非平庸相,在另... 详细信息

时间参数周期变化的弗洛凯系统有助于发现常参数静态系统中不存在并常常伴有新颖拓扑态出现的非传统拓扑相.耦合系数被周期调制的Su-Schrieffer-Heeger晶格正是这种弗洛凯系统之一.尽管这个晶格在一半演化周期内处在拓扑非平庸相,在另一半周期内处于拓扑平庸相,它的边界上仍然支持源于拓扑的反常π模.本文通过在透明非线性光学材料中刻蚀出周期振荡的Su-Schrieffer-Heeger波导阵列,分别实验观测到了一维系统中位于边界和二维系统中位于角落的光学反常π模.同时,在弗洛凯频谱的禁带中,作者还证实了在高功率情况下一类分化自光学反常π模的新拓扑π孤子.本文报道的π孤子是强振荡的非线性弗洛凯态,它们的波形在每经过一个纵向周期后都可以精确地复现.不论是在一维还是在二维振荡波导阵列中,这类π孤子都是动态稳定的,它们的局域特性都由其功率决定.二维的结果还表明作者实现了弗洛凯光学高阶拓扑绝缘体.

关键词： Floquet topological insulators p states Edge solitons SSH model

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